54 and 64
54 is much beefier action and bolt is more robust. For shooting tight groups would go with the 54. 64 is a good action but in my opinion there are better at least stronger built ones out there. CZ, 40X, 52 Win, Cooper Stiller customs others. I had one new 3 years ago that the bolt literally cracked on it luckily it was still in warranty allthough I paid the dang shipping to Annie shop. If you want a BR type rifle get a 54. Old used ones can be had for price of 64. you can get alot of replacement stuff too. JMO STBE